The TUC are campaigning for it to be made illegal for employers to keep their staff at work if the workplace temperature exceeds 30 degrees. They are also calling for more protection for outdoor workers and people who drive vehicles for a living.

With another heatwave on the way over the next few days, many hot and bothered workers across the UK will no doubt be wondering what their rights are regarding hotter than normal working conditions.

Union leaders believe there should be, and they argue this is, in fact, a serious health and safety issue. A spokesperson for the TUC has commented that overheating can cause heat cramps, dizziness and fainting. If the blood temperature rises above 39 degrees, delirium can set in. Sadly, cases have been known where this has proved fatal or has caused permanent organ damage.

The Health and Safety Executive (HSE) has currently issued no guidelines, in terms of a permitted maximum workplace temperature. The reasoning behind this is that workplaces vary so much from industry to industry, making a fixed maximum unworkable. For example, a metal foundry is naturally a much hotter environment to work in than a supermarket.

A spokesperson from HSE has also claimed that air temperature is actually only one of many factors that come into play, when health and safety is concerned. Amongst the other factors are air velocity, humidity and radiant temperature, and as temperatures rise, so the relationship between these elements becomes more complex. Therefore, as long as sufficient controls are in place to take all this into account, it can actually be perfectly safe to work at high temperatures.

As it stands then, the only official guidance comes from Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992, which states that indoor workplace temperatures must be “reasonable”. So, what of workers’ rights in the absence of an agreed maximum temperature? The HSE has stated that if a significant number of employees complain of being uncomfortable in the heat, employers are obliged to carry out a risk assessment and act upon the conclusions of this.

The HSE has also commented that some employees may be at a higher risk of suffering negative consequences from heat exposure, such as those going through the menopause, thyroid disorder patients and those who have to wear protective clothing. This should be taken into account when determining the impact of higher than normal workplace temperatures.

Overall, then, in terms of your rights as a worker, if enough people complain about the heat, employers are obliged to act, even in the absence of the standardised maximum temperature rules that the TUC are demanding.